1. Field of the General Inventive Concept
The present general inventive concept relates to an inkjet head chip including a plurality of nozzles and an inkjet print head including the inkjet head chip.
2. Description of the Related Art
In general, an inkjet type image forming apparatus refers to an apparatus which ejects ink from a shuttle type inkjet print head onto a sheet of printing paper in order to form an image, wherein the shuttle type inkjet print head shuttles in a main scanning direction, and the sheet of printing paper is transferred in a sub-scanning direction. An inkjet print head includes one or more inkjet head chips which include a plurality of nozzles discharging ink and a discharging unit providing an ink discharge pressure.
In order to realize high-speed printing, an array inkjet print head has been proposed. An array inkjet print head includes a nozzle unit having a length in a main scanning direction which corresponds to a width of a sheet of printing paper, instead of a shuttle type inkjet head. An inkjet type image forming apparatus using such an array inkjet print head transfers only sheets of printing paper in a sub-scanning direction. Therefore, a simple structure of a driving device of the inkjet type image forming apparatus and high-speed printing may be realized. A plurality of inkjet head chips are arrayed in a main scanning direction to cover a width of a sheet of printing paper in order to manufacture an array inkjet print head. The array inkjet print head may also be divided into two sub-heads which include nozzle units each having a length to correspond to half of the width of the sheet of printing paper. The two sub-heads are separated from each other by a predetermined space in the sub-scanning direction. Also, the two sub-heads may separately move in the main scanning direction. The two sub-heads may be positioned in a line in the main scanning direction to cover the whole width of the sheet of printing paper so as to print an image at a fixed position on the sheet of printing paper which is transferred in the sub-scanning direction. Both or one of the two sub-heads may be transferred in the main scanning direction in order to compensate for defective nozzles or improve resolution.
In general, inkjet head chips are manufactured using a similar process to a semiconductor manufacturing process such as a complementary metal-oxide semiconductor (CMOS) process, a micro-electromechanical systems (MEMS) process, or the like. A plurality of inkjet head chips are manufactured from one wafer. When inkjet head chips pass test printing and thus meet predetermined quality standards, they are applied to an inkjet print head. However, even if inkjet head chips manufactured using the same process meet predetermined quality standards, all of them may not have the same printing characteristics. For example, even if inkjet head chips are manufactured using the same process, discharge rates of ink, sizes of ink drops, and distances between nozzles may be slightly different. In the case of an inkjet print head using a plurality of inkjet head chips, in particular, an array inkjet print head, printing characteristic differences among the plurality of inkjet head chips are reflected on a printed image. Accordingly, manufacturing an inkjet print head using a plurality of inkjet head chips having similar printing characteristics becomes more difficult when favorable printing quality is desired.